Night Sky 101: Autumn Constellations Pegasus and Andromeda Pegasus, also known as “The Great Square,” is visible at the night sky’s zenith during the fall. The Andromeda constellation is directly attached to one of the points of Pegasus’s square. Andromeda is famous for M31, known commonly as The Andromeda Galaxy, which is the closest spiral galaxy to the Milky Way. It is also the brightest galaxy in the sky, and can be seen with the naked eye. The Andromeda Galaxy is positioned between the star Schedar, in Cassiopeia, and the star Mu Andromedae, in Andromeda. According to legend, the hero, Perseus, rescued Princess Andromeda from the monster Cetus on his flying horse, Pegasus. This is why Andromeda is depicted on Pegasus in the night sky – to immortal- ize her heroic rescue.
Perseus Perseus follows the constellation Cassiopeia across the sky, and is best seen in the northeastern autumn skies. Although it has been nicknamed “The Demon Star,” there is nothing sinister about Perseus’s star Algol. However, Al- gol is a variable binary star, meaning that it is actually two stars rotating around each other. A full rotation takes the two stars every 2 days and 20 hours. Algol’s brightness changes, depending on which star orbits in front. Before Perseus rescued Andromeda, he was a great hero. As the son of Zeus and the mortal Danae, Perseus was born with many gifts. He is best known for his killing of the hideous Gorgon, Medusa, who turned people to stone, simply by looking at them. He also used Medusa’s head to turn the Titan, Atlas, into a large mountain. In the constellation, the star Algol represents the Gorgon’s head.
Auriga (Pronounced or-EYE-gah) Auriga is located near Perseus in the night sky. It is easy to pick out Capella, the sixth brightest star in the autumn night sky, one of the points of a pentagon-like shape, which is the constellation Auriga. Ca- pella is a star that is very similar to our sun and is sometimes referred to as“ The Goat Star.” The stars next to it are called “The Kids.” Within Auriga, there are several star clusters, identified as M36, M37 and M38. These can be seen with binoculars. According to Greek Mythology, Auriga was the lame son of Hephaestus, god of the forge and craftsmen. Because Auriga couldn’t walk, he tamed four horses and built a chariot to carry himself around on. To reward his cleverness, Auriga was placed in the stars, on his chariot, by the gods.
For more information, visit our website, Information and photos credited to cpdarkskies.org earthsky.org